Performance Analysis and Enhancement of MAC Protocols

The challenge of designing an efficient Medium Access Control (MAC) protocol and analyzing it has been an important research topic for over 30 years. This thesis focuses on the performance analysis and enhancement of MAC protocols, particularly the random access protocols. Performance of the two widely known random access MAC protocols – the IEEE 802.3 MAC protocol that employs the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol, and the IEEE 802.11 MAC protocol that uses the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocol, are first studied. They are analyzed using a new analytical approach proposed in this thesis. The new approach is based on the idea that the service process of a MAC protocol can be modeled by a Phase-Type (PH) distribution. This way, the arrival process as well as the service process of the actual protocol can be described by a certain multidimensional continuous time Markov chain. The advantages of this novel technique over the traditional approach for performance analyses of MAC protocols are that: (i) it provides a unified model for the analysis of MAC protocols; (ii) it significantly simplifies the analytical model of a MAC protocol which makes it possible to include a more complex and realistic traffic model without compromising the protocol details; (iii) vast knowledge is available on the analysis of a continuous time Markov chain, which allows for more insight to the performance of a MAC protocol. Extensive demonstrations of the use of the approach on performance analyses of MAC protocols are provided, some of which conducted under realistic bursty traffic conditions. As a result of the performance analyses, it is found that the IEEE 802.3 MAC protocol exhibits relatively low and unattractive performance, especially when it is operated at 1Gb/s data rate. In response to this finding, two new protocols are introduced in this thesis. Firstly, we introduce a novel